Commercially available N-iodoamides, such as 1,3-diiodo-5,5-dimethylhydantoin (DIH, TCIMAIL No. 144, 2011) and N-iodosuccinimide (NIS e-EROS) are highly reactive iodination agents and are widely used in laboratory practice as efficient reagents for addition of iodine atom to alkene, substitution of hydrogen in aromatic compound with iodine, or substitution of carboxylic group in organic acid with iodine atom (WO2011154953A1; Adv. Synth. Catal. 2011, v. 353, 1438). The iodination with N-iodoamide gives a mixture of desired organic iodide and equimolar quantity of amide as co-product. The water soluble amide is separated from the lipophilic organic iodide by water treatment. Ease of separation of reaction products from side products determines the success and popularity of the stable N-iodoamides as iodination agents in laboratory practice. However, the lack of 5,5-dimethylhydantoin and succinimide recovery processes limit the use of 1,3-diiodo-5,5-dimethylhydantoin and N-iodosuccinimide in the industry. In ideal case, the amide co-products must be soluble in water and at the same time can be easily recovered from aqueous solutions. It would seem that N-iodosaccharin (NISac) is suitable on the role of the ideal iodination agent as saccharin is soluble in aqueous alkali and precipitated after acidification. However, the scope of use of NISac is limited by the reactions of electrophilic iodination (Synlett 2000, 544). Thus search for a new generation of stable N-iodoamides suitable for radical and electrophilic iodination is an actual problem.
N-iodoamide for industrial use should possess high stability in pure state and high reactivity in radical and electrophilic reactions. Method of preparation of the N-iodoamide should be simple and effective. Corresponding amide must be soluble in water and, at the same time, can be easily recovered from aqueous solutions.